Control system for roller mills

ABSTRACT

A GRAIN ROLLER MILL INCLUDING A PAIR OF ROTATABLE ROLLS BETWEEN WHICH THE GRAIN IS MILLED, A CONTROL SYSTEM COMPRISING A FLUID POWER ACTUATOR FOR APPLYING EQUAL FORCES TO OPPOSITE ENDS OF ONE OF THE ROLLS WHEREBY EQUAL ROLLING PRESSURE IS APPLIED BY THE ROLLS THROUGHOUT THE LENGTH OF THE ROLLS, AND   A FLUID PRESSURE GENERATOR COMMUNICATING WITH THE FLUID POWER ACTUATOR.

United States Patent Inventor Charles J. Aiciati Alamo, Calif.

Appl. No. 747,880

Filed July 26, 1968 Patented June 28, 1971 Assignee M11 Engineering & Machinery Co.

Oakland, Calif.

CONTROL SYSTEM FOR ROLLER MILLS 4 Chills, 4 Drawing Figs.

US. Cl 241/231 Int. Cl 1102c 4/06, 1302c 4/38 Field 01 Search 241/231,

[56] References Cited UNITED STATES PATENTS 1,788,964 1/1931 Vasel 241/231X 3,010,663 11/1961 Bosshard 241/231X 3,099,406 7/1963 Kautz 241/32 3,445,070 5/1969 Verdier 241/37 Primary Examiner-Donald G. Kelly Attorney-Townsend and Townsend ABSTRACT: A grain roller mill including a pair of rotatable rolls between which the grain is milled, a control system oomprising a fluid power actuator for applying equal forces to opposite ends of one of the rolls whereby equal rolling pressure is applied by the rolls throughout the length of the rolls, and a fluid pressure generator communicating with the fluid power actuator.

PATENTED JUN28197l 'sum 1 or 2 FIG.2

lNVl'fNTUR.

CHARLES J- ALCIATI BY ATTORNEYS PATENTEDJuuzsXsn sum 2 0F 2 FIGS TO PUMP INVENTOR. CHARLES J. ALCIATI F IG. 4 BY ATTORNEYS CONTROL SYSTEM FOR ROLLER MILLS BACKGROUND OF THE INVENTION 'The present invention relates to grain roller mills and, more particularly, to an improved control system for grain roller mills of the type adapted for milling barley, oats, corn and the like for animal feed.

Heretofore, grain roller mills have been provided which included a plurality'ofrollsbetween which grain is passed to mill the grain for animal feed purposes. In' such prior roller mills, one of a pair of rolls is usually mounted for rotation about a fixed axis and the other of the pair of rolls is mounted for rotation about an axis supported for pivotal movement relative to the axis of rotation of the first roll. Adjusting screws are provided at opposite ends of the pivotally supported roll, the adjusting screws being manually rotatable so that the pivotally supported roll may be moved toward and away from the fixed axis roll to adjust the clearance and the rolling pressure between the rolls. Such prior roller mills are difficult to adjust and require time-consuming manual effort to align the rolls and equalize the forces applied by the adjusting screws so that uniform rolling pressures are obtained throughout the length of the rolls. Prior rolling mills also utilize manually actuated cam members requiring substantial manual effort to release the rolls quickly in the event foreign material is encountered which could damage the rolls.

SUMMARY OF THE INVENTION The present invention overcomes the above as well as the other shortcomings of the prior art and, according to one form of the present invention, a roller mill is provided comprising a pair of rotatable milling-rolls which function to mill the grain as the grain passes therebetween, means being provided for driving the rolls in opposite angular directions. A pair of hydraulic power actuators are provided at opposite ends of the rolls, the hydraulic power actuators being adapted to apply equal forces to the opposite ends of one of the rolls whereby uniform rolling pressures are obtained throughout the full length of the rolls. The hydraulic power actuators are connected to a common source of fluid pressure whereby the application of equal forces to both ends of one of the rolls is as sured. The fluid pressure source is controlled by a pressure switch which may be manually adjusted to limit the output pressure of the source to any desired predetermined pressure, and a manually actuated valve is provided which, when actu ated, is effective to drop the operating pressure applied to the hydraulic power actuators and effects separation of the rolls.

It is an object of the present invention to provide an improved control system for roller mills of the indicated character. It is another object of the present invention to provide an improved control system for roller mills which assures equal rolling pressure throughout the length of the rolls and which is operative to release the closing pressure applied to the rolls easily and quickly and with a minimum of manual effort. It is a further object of the present invention to provide an improved control system for roller mills that is simple in construction, economical to manufacture, durable, efficient and reliable in operation.

Other objects and advantages of the present invention will become apparent from the following description, the appended claims and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a roller mill embodying the present invention;

FIG. 2 is a side elevational view, with portions in cross section, of a portion of the structure illustrated in FIG. 1;

FIG. 3 is an end view of a portion of the structure illustrated in FIG. I; and

FIG. 4 is an elevational view of the fluid pressure generating means illustrated in FIG. 1.

2 DESCRIPTION OF THEIREFERRED EMBODIMENT Referring to the drawings, a rolling mill, generally designated 10, is illustrated which is comprised of a base 12 mounted on legs 14, the base carrying a pair of rotatable milling rolls l6 and 18 that function to mill the grain as the grain passes therebetween. The roll 16 is mounted on a shaft 20 supported for rotation by a pair of stationary bearing housings 22 fixed to the base 12 on the opposite sides of the base. The roll 18 is mounted on a shaft 24 supported for rotation by a pair of pivotally mounted bearing housings 26 disposed on opposite sides of the base 12 and pivotally connected to the base through the agency of pivot pins 28.

A housing, generally designated 30, is provided which encloses the rolls 16 and 18 and the lower end of which is fixed to the base 12, the housing 30 having a converging chute portion 32 which serves to confine and funnel the grain between the rolls 16 and 18.

Means is provided for driving the rolls l6 and 18, the driving means comprising a pulley 34 fixed to one end of the shaft 20, the pulley 34 being driven by a belt 36 which extends over a pulley 38 mounted on the drive shaft 40 of an electric motor 42 fixed to the base 12. A pulley (not shown) similar to the pulley 34 is mounted on the end of the shaft 20 remote from the pulley 34 and functions to drive a pulley 46 fixed to the shaft 24 through the agency of a belt 48 which engages the lower surface of the pulley 46 and also extends over an idler pulley 50 mounted on a shaft 52 carried by bearing blocks 54 and 56 fixed to the opposite sides of one end of the base 12.

With such a construction, the rolls l6 and 18 are driven in 'opposite angular directions as viewed in FIG. 2.

In accordance with the present invention, control means is provided for adjusting the distance between the peripheral surfaces of the rolls l6 and 18 and applying equal forces to both ends of the roll 18 whereby uniform rolling pressure is assured throughout the full length of the rolls l6 and 18. Such control means is comprised of a pair of hydraulic power actuators generally designated 58 and 60, mounted on opposite sides of the base 12. Each of the power actuators 58 and 60 is comprised of a piston and cylinder unit 62 which is mounted on one end of a rod 64. The rod 64 extends througha bore 66 provided in an arm portion 68 of the adjacent bearing housing 26, the arm portion 68 of the bearing housing 26 projecting upwardly, as viewed in FIG. 2, from the main body portion 70 of the bearing housing 26 in a direction diametrically opposite the pivot pin 28. The bore 66 is sufficiently large to permit the desired pivotal or angular movement of the bearing housings 26 as will be described hereinafter in greater detail. The rod 64 also extends through aligned bores 72 and 74 provided in a pair of arm portions 76 and 78 projecting upwardly from the main body portion 80 of the fixed bearing housings 22.

Each of the piston and cylinder units 62 includes a cylinder body 82 defining a bore 84 in which is disposed a hollow piston 86 that is mounted for reciprocating movement in the bore 84 and for sliding movement relative to the rod 64. The head end of the bore 84 is provided with a hydraulic fluid inlet 88 which communicates with a source of hydraulic fluid under pressure, as will be described hereinafter in greater detail. A return spring 90 is provided at the rod end of the cylinder, the spring 90 surrounding the anvil portion 92 of the piston 86 with one end of the spring 90 bearing against the pistonhead and the other end of the spring bearing against the end 94 of the cylinder 82. The anvil portion 92 of the piston 86 projects out of the cylinder 82 and bears against the face 96 of the arm portion 68 of the housing 26. A sleeve-type stop member 98 is provided which is mounted on the rod 64 intermediate the arm portions 68 and 76 of the bearing housings 26 and 22, respectively, and a return spring 100 is provided which surrounds the sleeve 98, one end of the spring 100 bearing against a fixed, radially projecting flange 102 provided on the sleeve 98 intermediate the ends thereof, while the opposite end of the spring 100 bears against a washer 104 mounted for sliding movement on the rod 64 and abutting the face 106 of the arm portion 68. The left end of the sleeve 98, as viewed in FIG. 2, abuts a washer 108 which bears against an adjustable stop member 110 threadably engaging the arm portion 76 of the housing 22, a locknut 112 being provided to retain the adjustable stop member 110 in the selected, adjusted position.

in the embodiment of the invention illustrated, a filler sleeve 114 surrounds the rod 64 between the arm portions 76 and 78 of the housing 22 and the assembled components of each power actuator are retained in assembled condition through the agency of locknuts such as 116 and 118, which threadably engage the opposite end portions of the rod 64, an alignment sleeve such as 120 being provided in the bore 74 of the arm portion 78 to assure proper alignment of the rod within the bores 72 and. 74 of the arm portions 76 and 78.

As shown in FIGS. 3 and 4, the inlets 88 of the piston and cylinder units 62 of the hydraulic actuators 58 and 60 are connected to a common source of fluid under pressure through supply lines 122 and 124, a tee connection 126, and a supply line 128. in order to support the supply lines 122, 124 and 128, a support member 125 is provided which is carried by the rod 64, the support member 125 having depending flanges 127 and 129 supporting the supply lines. Suitable swivel connections, such as 130, may be provided, if desired, to facilitate positioning of the supply line 128.

The supply line 128 is connected to a pump 132 driven by a motor 134 that may be electrically connected to any suitable source of electric power. The outlet 136 of the pump communicates with the supply line 128 through a check valve 138, a cross-connection 140 and a supply line 142. The output 136 of the pump also connects with a pair of conventional nitrogen filled accumulators 144 and 145, the accumulator 144 being a low pressure accumulator and being connected through a tee connection 146 to the supply line 142. The accumulator 145 is connected to the pump through the cross-connection 140. The accumulators 144 and 145 are intended to be used alternately so as to apply pressure to the hydraulic actuators 58 and 60, the accumulator 144 having a relatively low pressure range, as for example in the order of 400 p.s.i. while the accumulator 145 is intended to apply relatively high pressure to the hydraulic actuators and may by way of example, apply a pres sure of the order of 1,300 p.s.i. With such a construction, a wide variety of grain may be milled under different rolling pressures. If a narrower range of operation is sufficient, only one accumulator need be provided. Flow of fluid to the accumulators 144 and 145 is controlled by manually actuated valves 149 and 150. The output 136 of the pump also communicates with a pressure gauge 148 connected to the supply line 142 by conventional fittings, and a return line 152 is provided having a manual valve 154 which is interposed between the line 142 and the line 128 and which may be opened to release the pressure in the hydraulic system and provide a direct return of hydraulic fluid to the pump. The output of the pump is controlled by a conventional pressure switch 156 which may be manually adjusted by a knob 157 to limit the output of the pump to any desired predetermined pressure within the design limitations of the pump and which functions to maintain the operating pressure in the piston and cylinder units at any desired level whereby once the desired operating pressure is reached the pump is inactive during operation of the rolling mill except when the pressure in the selected accumulator 144' or 145 falls below the desired operating pressure.

In the operation of the roller mill 10, the roll 18 is initially adjusted so that the desired clearance is obtained between the peripheral surfaces of the rolls 16 and 18 by adjusting the ad justable stop members 110 which threadably engage the arm portions 76 of the housings 22. it will be apparent that when the stop member 110 is in a selected adjusted position, it provides a positive stop for the adjacent end of the sleeve 98 acting through the washer 108, and the sleeve 98, in turn, provides a positive stop for the arm portion 68 of the pivotally supported housing 26 when the surface 106 of the arm portion 68 abuts the washer 104 bearing against the adjacent end of the sleeve 98. v

After the minimum desired clearance is set between the peripheral surfaces of the rolls 16 and 18, the pressure switch 156 is adjusted so as to limit the output of the pump 132 to the desired operating pressure/The motor 134 is then energized and with the valve 154 in closed position the pressure will build up in the selected accumulator 144 or 145 and in the piston and cylinder units 62 of the hydraulic actuators 58 and 60 so that the piston 86 acting through the anvil portion 92 thereof bearing against the surface 96 of the arm portion 68 of the housing 26 will pivot the housing 26 about the axis of the pivot pin 28 thereby pivoting the roll 18 about the axis of the pivot pin toward the roll 16, and the roll 18 will move angularly until the surface 106 of the arm portion 68 and the washer 104 abut the adjacent end of the sleeve 98, the angular movement of the arm portion 68 being resisted by the return springs and 100. Since the piston and cylinder units 62 of the power actuators 58 and 60 are connected to the accumulators 144 and 145 through a common supply line 128, the forces applied by the power actuators 58 and 60 to the opposite ends of the roll 18 will be identical, and the rolling pressure throughout the length of the rolls l6 and 18 will be uniform.

The grain which is to be milled is placed in the housing 30 above the rolls 16 and 18, so that the grain is conveyed by the chute portion 32 between the rolls 16 and 18, and the milled grain may be removed from below the rolls by any desired means.

In the event it is desired to separate the rolls 16 and 18, as for example when foreign material is encountered which might damage the rolls, the valve 154 is manually opened thereby immediately dropping the pressure in the piston and cylinder units 62 and the accumulators 144 or 145 by opening the line 152 which leads to the inlet or sump of the pump 132. The springs 90 and then function to return the pistons 86 to the head end of the cylinders and to pivot the arm portions 68 of the housings 26 about the axis of the pivot pins 28 in a clockwise direction, as viewed in FIG. 2, so as to move the roll 18 away from the roll 16. The roll 18 may be immediately returned to the preselected rolling position with respect to the roll 16 merely by closing the valve 154. When the valve 154 is closed the pressure in the selected accumulator 144 or and the piston and cylinder units 62 will then immediately build up to the preselected pressure controlled by the pressure switch 156 and the roll 18 will automatically return to the selected rolling position.

After the pressure in the selected accumulator 144 or 145 reaches the desired preselected pressure, the switch 156 will open the circuit controlling the motor 134 with the result that the pump 132 will stop and will only be operative when the pressure in the selected accumulator and the piston and cylinder units 62 falls below the desired operating pressure. Such a construction minimizes heating of the hydraulic fluid and wear of the compressor 132 and the motor 134.

While a preferred embodiment of the invention has been shown and described, it will be understood that various changes and modifications may be made without departing from the spirit of the invention.

lclaim:

1. A grain roller mill comprising a fixed roller supported at its ends by stationary bearings, a movable roller supported at its ends by bearings mounted in pivot arms so that the movable roller may be pivoted into contact with the fixed roller, a connecting rod connected between each pivot arm and the stationary bearing opposite each arm, biasing means mounted on each rod between the stationary bearing and the pivot arm for maintaining the separation between the fixed and the movable rollers, and fluid pressure means mounted at one end of each said rod for forcing the pivot arms carrying the movable roller toward the fixed roller.

2. The grain roller mill as set forth in claim 1 including stop means mounted on each of the rods for limiting the pivotal travel of the pivot arms toward the fixed roller.

3. The grain roller mill as set forth in claim 1 wherein each pivot arm has a bore therethrough, said bore having a diameter larger than that of the rod received therein for connection to each arm, the spacing between the rod and the inside diameter of the bore permitting the arm to pivot through a small angle without movement of the rod.

4. The grain roller mill as set forth in claim 3 wherein the fluid pressure means comprise a piston cylinder unit opera- 

